content: /* ===========================================================
   * JFreeChart : a free chart library for the Java(tm) platform
   * ===========================================================
   *
   * (C) Copyright 2000-2012, by Object Refinery Limited and Contributors.
   *
   * Project Info:  http://www.jfree.org/jfreechart/index.html
   *
   * This library is free software; you can redistribute it and/or modify it
   * under the terms of the GNU Lesser General Public License as published by
   * the Free Software Foundation; either version 2.1 of the License, or
   * (at your option) any later version.
   *
   * This library is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
   * License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this library; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
   * USA.
   *
   * [Oracle and Java are registered trademarks of Oracle and/or its affiliates.
   * Other names may be trademarks of their respective owners.]
   *
   * -----------------------
   * AbstractAnnotation.java
   * -----------------------
   * (C) Copyright 2009, by Object Refinery Limited and Contributors.
   *
   * Original Author:  Peter Kolb (see patch 2809117);
   * Contributor(s):   ;
   *
   * Changes:
   * --------
   * 20-Jun-2009 : Version 1 (PK);
   *
   */
  
  package org.jfree.chart.annotations;
  
  import java.io.IOException;
  import java.io.ObjectInputStream;
  import java.io.ObjectOutputStream;
  import java.io.Serializable;
  import java.util.Arrays;
  import java.util.EventListener;
  import java.util.List;
  
  import javax.swing.event.EventListenerList;
  
  import org.jfree.chart.event.AnnotationChangeEvent;
  import org.jfree.chart.event.AnnotationChangeListener;
  
  /**
   * An abstract implementation of the {@link Annotation} interface, containing a
   * mechanism for registering change listeners.
   *
   * @since 1.0.14
   */
  public abstract class AbstractAnnotation implements Annotation, Cloneable,
          Serializable {
  
      /** Storage for registered change listeners. */
      private transient EventListenerList listenerList;
  
      /**
       * A flag that indicates whether listeners should be notified
       * about changes of the annotation.
       */
      private boolean notify = true;
  
      /**
       * Constructs an annotation.
       */
      protected AbstractAnnotation() {
          this.listenerList = new EventListenerList();
      }
  
      /**
       * Registers an object to receive notification of changes to the
       * annotation.
       *
       * @param listener  the object to register.
       *
       * @see #removeChangeListener(AnnotationChangeListener)
       */
      @Override
      public void addChangeListener(AnnotationChangeListener listener) {
          this.listenerList.add(AnnotationChangeListener.class, listener);
      }
  
      /**
       * Deregisters an object so that it no longer receives notification of
       * changes to the annotation.
       *
       * @param listener  the object to deregister.
       *
       * @see #addChangeListener(AnnotationChangeListener)
       */
      @Override
      public void removeChangeListener(AnnotationChangeListener listener) {
          this.listenerList.remove(AnnotationChangeListener.class, listener);
      }
  
      /**
       * Returns <code>true</code> if the specified object is registered with
       * the annotation as a listener.  Most applications won't need to call this
       * method, it exists mainly for use by unit testing code.
       *
       * @param listener  the listener.
       *
       * @return A boolean.
       *
       * @see #addChangeListener(AnnotationChangeListener)
       * @see #removeChangeListener(AnnotationChangeListener)
       */
      public boolean hasListener(EventListener listener) {
          List<Object> list = Arrays.asList(this.listenerList.getListenerList());
          return list.contains(listener);
      }
  
      /**
       * Notifies all registered listeners that the annotation has changed.
       *
       * @see #addChangeListener(AnnotationChangeListener)
       */
      protected void fireAnnotationChanged() {
          if (notify) {
              notifyListeners(new AnnotationChangeEvent(this, this));
          }
      }
  
      /**
       * Notifies all registered listeners that the annotation has changed.
       *
       * @param event  contains information about the event that triggered the
       *               notification.
       *
       * @see #addChangeListener(AnnotationChangeListener)
       * @see #removeChangeListener(AnnotationChangeListener)
       */
      protected void notifyListeners(AnnotationChangeEvent event) {
  
          Object[] listeners = this.listenerList.getListenerList();
          for (int i = listeners.length - 2; i >= 0; i -= 2) {
              if (listeners[i] == AnnotationChangeListener.class) {
                  ((AnnotationChangeListener) listeners[i + 1]).annotationChanged(
                          event);
              }
          }
  
      }
  
      /**
       * Returns a flag that indicates whether listeners should be
       * notified about changes to the annotation.
       *
       * @return  the flag.
       *
       * @see #setNotify(boolean)
       */
      public boolean getNotify(){
          return this.notify;
      }
  
      /**
       * Sets a flag that indicates whether listeners should be notified about
       * changes of an annotation.
       *
       * @param flag  the flag
       *
       * @see #getNotify()
       */
      public void setNotify(boolean flag){
          this.notify = flag;
          if (notify) {
              fireAnnotationChanged();
          }
      }
  
      /**
       * Returns a clone of the annotation. The cloned annotation will NOT
       * include the {@link AnnotationChangeListener} references that have been
       * registered with this annotation.
       *
       * @return A clone.
       *
       * @throws CloneNotSupportedException  if the annotation does not support
       *                                     cloning.
       */
      @Override
      public Object clone() throws CloneNotSupportedException {
          AbstractAnnotation clone = (AbstractAnnotation) super.clone();
          clone.listenerList = new EventListenerList();
          return clone;
      }
  
      /**
       * Handles serialization.
       *
       * @param stream  the output stream.
       *
       * @throws IOException if there is an I/O problem.
       */
      private void writeObject(ObjectOutputStream stream) throws IOException {
          stream.defaultWriteObject();
      }
  
      /**
       * Restores a serialized object.
       *
       * @param stream  the input stream.
       *
       * @throws IOException if there is an I/O problem.
       * @throws ClassNotFoundException if there is a problem loading a class.
       */
      private void readObject(ObjectInputStream stream)
          throws IOException, ClassNotFoundException {
          stream.defaultReadObject();
          this.listenerList = new EventListenerList();
      }
  
  }
  